Locking hinge for folding ladder

Abstract

A hinge for a folding ladder including a hinge latch movable between a locked position and an unlocked position disposed within a hinge latch cavity. The hinge latch includes a first locking portion protruding therefrom, an elongated slot formed configured to slidingly receive a hinge shaft, a first opening configured to receive a first biasing member, and a second opening configured to receive a locking member. Rotational movement of one hinge casing relative to another hinge casing is prevented by engagement of the first locking portion and locking member with a respective one of the first opening and second opening.

1. A foldable ladder configured for installation in an opening to provide access between one floor or space and another floor or space, comprising:
 an upper ladder section having at least one rail; 
 a lower ladder section having at least one rail; 
 a locking hinge connecting the rail of the upper ladder section to the rail of the lower ladder section and configured to allow the lower ladder section to fold relative to the upper ladder section, wherein 
 when the upper ladder section and the lower ladder section are fully unfolded, the locking hinge being adjustable between at least two configurations, 
 in a first configuration, the locking hinge completely preventing the lower ladder section from folding relative to the upper ladder section, and 
 in a second configuration, the locking hinge allowing the lower ladder section to fold relative to the upper ladder section; wherein 
 the locking hinge comprises: 
 a hinge latch positioned between the first and second opposing hinge plates, the
 hinge latch comprising an angle latch portion and the hinge latch being movable between a locked position and an unlocked position, wherein biasing the hinge latch from the locked position to the unlocked position adjusts the locking hinge from the first configuration to the second configuration; 
 a plurality of hinge plates; 
 a first biasing member biasing the hinge latch towards the locked position; 
 a second biasing member, wherein upon the hinge latch being in the unlocked position, the first biasing member being prevented by the second biasing member from biasing the hinge latch towards the locked position; and 
 a third biasing member, wherein upon rotational movement of the hinge plates the angled latch portion contacts the third biasing member allowing the first biasing member to bias the hinge latch towards the locked position. 
 
 
     
     
       2. The foldable ladder according to  claim 1 , wherein when the angled latch portion contacts the third biasing member the second biasing member disengages thereby allowing the first biasing member to bias the hinge latch towards the locked position. 
     
     
       3. The foldable ladder according to  claim 1 , wherein the first biasing member comprises a spring. 
     
     
       4. The foldable ladder according to  claim 1 , wherein the second biasing member is a spring plunger comprising a spring-loaded plunger ball. 
     
     
       5. The foldable ladder according to  claim 1 , wherein the hinge plates comprise the third biasing member. 
     
     
       6. The foldable ladder according to  claim 5 , wherein the third biasing member is an angled plate portion of the hinge plates.